US7804286B2 - Multiple output amplifiers and comparators - Google Patents
Multiple output amplifiers and comparators Download PDFInfo
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- US7804286B2 US7804286B2 US11/850,494 US85049407A US7804286B2 US 7804286 B2 US7804286 B2 US 7804286B2 US 85049407 A US85049407 A US 85049407A US 7804286 B2 US7804286 B2 US 7804286B2
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
Definitions
- the present invention relates to integrated circuits, and more particularly to switching voltage regulators formed in an integrated circuit.
- Voltage regulators are often used to generate a lower DC voltage from a higher, unstable DC supply voltage.
- One type of voltage regulator commonly referred to as a switching voltage regulator, typically includes a switching element, such as a transistor, and an inductor disposed between the voltage source and an output load.
- the switching regulator regulates the voltage across the load by turning the switching element on and off, thereby enabling current pulses to be delivered from the voltage source to the inductor.
- the inductor together with a capacitor convert the current pulses to a substantially constant load current so as to regulate the load voltage.
- FIG. 1 is a schematic diagram of a current-mode step-down switching regulator 100 , as known in the prior art.
- current is supplied to inductor 118 by closing switch 128 and opening switch 126 .
- current is withdrawn from inductor 118 by closing switch 126 and opening switch 128 .
- Switches 126 and 128 are opened and closed in response to control signals C 1 and C 2 generated by control logic 110 .
- Amplifier 102 may be a transconductance amplifier and is alternatively referred to below as an error amplifier. Amplifier 102 is adapted to generate a signal VI TH that is proportional to a difference between voltage V FB and a reference V Ref . Reference voltage V Ref may be supplied by a bandgap circuit and is adapted so as not to vary substantially with supply voltage, temperature, etc.
- Compensation circuit 142 is coupled to the output terminal of amplifier 102 when switch 140 —shown as being responsive to signal Sleep—is closed. Compensation circuit 142 stabilizes amplifier 102 against a number of factors, such as supply voltage variations, temperature changes, etc, as is well known in the art.
- Hysteretic comparator 104 is adapted to compare signal VI TH with reference voltage V B1 . If voltage VI TH is detected as being higher than an upper level of a voltage band defined by reference voltage V B1 , output voltage Sleep of comparator 104 switches to a high state. If, on the other hand, voltage VI TH is detected as being smaller than a lower level of the voltage band defined by reference voltage V B1 , output voltage Sleep of comparator 104 switches to a low level.
- signal Sleep When signal Sleep is asserted, e.g., is at a high level, compensation circuit 142 is decoupled from amplifier 102 , voltage limiter 106 is shut down, signal C 1 causes switch 128 to go into a high-impedance mode, and signal C 2 causes switch 126 to go into high-impedance mode when the switch current approaches zero, thus placing voltage regulator 100 in a standby mode so as to reduce the quiescent current.
- comparator 104 switches again, thereby causing signal Sleep to be de-asserted to resume normal operation.
- Voltage limiter 106 compares voltage signal VI TH with another reference voltage V B2 . If voltage signal VI TH is detected as being greater than voltage level V B2 , voltage limiter 106 delivers output voltage signal VI TH at its output terminal unchanged. If signal VI TH is detected as being smaller than voltage level V B2 , voltage limiter 106 clamps signal VI TH to voltage level V B2 and delivers the voltage level V B2 at its output terminal. In other words, voltage limiter 106 ensures that its output voltage V clamp does not fall below voltage level V B2 .
- Control logic 110 receives signals Sleep and B, and in response generates control signals C 1 and C 2 . If signal B is at, e.g., a low logic level, signals C 1 and C 2 are respectively caused to be at high and low levels, thereby causing switch 128 to be on and switch 126 to off. In other words, if voltage V 1 is detected as being smaller than voltage V clamp , switch 128 is turned on and switch 126 is turned off. Accordingly, current I 1 is enabled to flow to inductor 118 and resistor 122 to thereby raise output voltage V out .
- signals C 1 and C 2 are respectively caused to be at low and high levels, thereby causing switch 128 to turn off and switch 126 to turn on.
- voltage V 1 is detected as being greater than voltage V clamp
- switch 128 is turned off and switch 126 is turned on. Accordingly, current I 2 is withdrawn from inductor 118 and resistor 122 to thereby decrease output voltage V out .
- Switch regulator 110 is also shown as including comparators 112 and 114 , as well oscillator 130 .
- Comparator 112 is adapted to assert its output signal V under if comparator 112 detects that feedback voltage V FB is smaller than voltage V ref ⁇ V.
- Comparator 114 is adapted to assert its output signal V over if comparator 114 detects that feedback voltage V FB is greater than voltage V ref + ⁇ V , where ⁇ V is a predefined voltage level.
- Oscillator 130 supplies a clock signal to control logic 110 .
- the amount of ripple appearing at output voltage V OUT is determined, in part, by the difference between the trip points of comparator 104 divided by the gain of amplifier 102 . Therefore, to decrease such ripples, the difference between the trip points of comparator 104 is required to be reduced and/or the gain of amplifier 102 is required to increase. As is well known, the gain of amplifier 102 is dependent, in part, on the electrical characteristics of the components disposed in compensation block 142 . While compensation circuit 142 stabilizes amplifier 102 it also loads the negative input terminal of comparator 104 . This loading causes comparator 104 to be relatively slow and unable to follow the variation in output signal V OUT , in turn, causing ripples to appear on signal V OUT .
- the multi-output amplifier/comparator is disposed in a current-mode switching regulator adapted to generate a lower DC voltage from a higher unstable DC power supply.
- FIG. 1 is a schematic diagram of a current-mode switching regulator, as known in the prior art.
- FIG. 2 is a schematic diagram of a current-mode switching regulator, as known in the prior art.
- FIG. 3 is a schematic diagram of a current-mode switching regulator, in accordance with one embodiment of the present invention.
- FIG. 4 is a transistor schematic diagram of the error amplifier and the burst comparator disposed in the switching regulator of FIG. 3 , in accordance with one exemplary embodiment of the present invention.
- FIG. 6 is a transistor schematic diagram of a multi-output amplifier/comparator, in accordance with one exemplary embodiment of the present invention.
- FIG. 3 is a schematic diagram of a switching regulator 300 , in accordance with one exemplary embodiment of the present invention.
- Switching regulator 300 is shown as including, in part, a dual-output amplifier/comparator 350 .
- Switching regulator 300 is also shown as including, in part, compensation block 142 , voltage limiter 106 , comparators 108 , 112 , 114 , control logic 110 , resistor 116 , switches 126 , 128 , inductor 118 , capacitor 120 , resistive load 122 and oscillator 130 ; these blocks are similar to those described with reference to FIG. 1 and thus are not described further.
- both output stages 450 and 460 share the same input stage 430 , in accordance with the present invention. Accordingly, relatively small amount of input offset exists between the amplifier—defined, in part, by input stage 430 and output stage 460 —and the comparator defined, in part, by input stage 430 and output stage 450 . Furthermore, because the input stage 430 of the comparator is not loaded by the compensation block 142 , in accordance with the present invention, the comparator operates at a high speed thus minimizing output ripple voltage.
- Transistors 406 and 408 are active load transistors that are also respectively adapted to pass currents I 1 and I 2 .
- Current I s supplied by current source 435 is equal to the sum of currents I 1 and I 2 and is used to bias differential input stage 430 . Since transistors 406 and 412 have the same gate-to-source voltage, current I 1 also flows through transistor 412 .
- Transistors 410 and 412 have the same drain current, therefore current I 1 also flows through transistor 410 .
- Transistor 414 is selected to have a channel-width (W) to channel length (L) ratio that is M times the W/L of transistor 410 , where M is greater than zero. Because transistors 414 and 410 have the same gate-to-source voltage, current I 3 flowing through transistor 414 is equal to M ⁇ I 1 .
- Transistor 416 is selected to have a W/L ratio that is N times the W/L of transistor 408 , where N is greater than zero. Because transistors 408 and 416 have the same gate-to-source voltage, current I 4 flowing through transistor 416 is equal to N ⁇ I 1 .
- FIG. 5 is a schematic diagram of a switching regulator 500 , in accordance with another exemplary embodiment of the present invention.
- Switching regulator 500 is similar to switching regulator 300 except that multi-output amplifier 450 disposed in switching regulator 500 , in addition to delivering amplified signal VI TH and comparison signal Sleep, also delivers additional compare signals V over , and V under each generated in accordance with a different trip point.
- multi-output amplifier 450 performs the various functions associated with amplifier 102 , and comparators 104 , 112 and 114 of switching regulator 100 , shown in FIG. 1 .
- the above embodiments of the present invention are illustrative and not limitative. Various alternatives and equivalents are possible.
- the invention is not limited by the type of transistors, bipolar, MOS or otherwise, that may be used to form the amplifiers, comparators, etc.
- the invention limited by the type of circuit, switching regulator or otherwise, in which the multi-output amplifier of the present invention may be embodied.
- the invention is not limited by the type of integrated circuit in which the present disclosure may be disposed.
- the invention limited to any specific type of process technology, e.g., CMOS, Bipolar, BICMOS, or otherwise that may be used to form the differential amplifier of the present invention.
- Other additions, subtractions or modifications are obvious in view of the present invention and are intended to fall within the scope of the appended claims.
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US11/850,494 US7804286B2 (en) | 2007-09-05 | 2007-09-05 | Multiple output amplifiers and comparators |
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US11/850,494 US7804286B2 (en) | 2007-09-05 | 2007-09-05 | Multiple output amplifiers and comparators |
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US20090058380A1 US20090058380A1 (en) | 2009-03-05 |
US7804286B2 true US7804286B2 (en) | 2010-09-28 |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110176694A1 (en) * | 2010-01-13 | 2011-07-21 | Schurr Thomas H | Multi-port combiner for an audio amplifier |
US8717070B1 (en) | 2013-03-12 | 2014-05-06 | Cypress Semiconductor Corporation | Multifunctional configurable analog circuit block, methods, and integrated circuit devices having the same |
WO2024084911A1 (en) * | 2022-10-17 | 2024-04-25 | ローム株式会社 | Voltage monitoring circuit, semiconductor integrated circuit device, vehicle, control device, switching regulator, and power supply device |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108631738B (en) * | 2018-05-08 | 2022-08-19 | 湖南国科微电子股份有限公司 | Operational amplifier, operational amplifier circuit and driving chip |
US11703898B2 (en) * | 2021-07-09 | 2023-07-18 | Allegro Microsystems, Llc | Low dropout (LDO) voltage regulator |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6486736B2 (en) * | 2000-03-09 | 2002-11-26 | Stmicroelectronics S.R.L. | Class AB single-range advanced operational amplifier |
US6566951B1 (en) * | 2001-10-25 | 2003-05-20 | Lsi Logic Corporation | Low voltage variable gain amplifier having constant common mode DC output |
US7053711B2 (en) * | 2003-09-19 | 2006-05-30 | Infineon Technologies Ag | Multistage differential amplifier |
US7253686B2 (en) * | 2005-07-27 | 2007-08-07 | Analog Devices, Inc. | Differential amplifiers with enhanced gain and dynamic range |
US7489186B2 (en) * | 2006-01-18 | 2009-02-10 | International Rectifier Corporation | Current sense amplifier for voltage converter |
-
2007
- 2007-09-05 US US11/850,494 patent/US7804286B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6486736B2 (en) * | 2000-03-09 | 2002-11-26 | Stmicroelectronics S.R.L. | Class AB single-range advanced operational amplifier |
US6566951B1 (en) * | 2001-10-25 | 2003-05-20 | Lsi Logic Corporation | Low voltage variable gain amplifier having constant common mode DC output |
US7053711B2 (en) * | 2003-09-19 | 2006-05-30 | Infineon Technologies Ag | Multistage differential amplifier |
US7253686B2 (en) * | 2005-07-27 | 2007-08-07 | Analog Devices, Inc. | Differential amplifiers with enhanced gain and dynamic range |
US7489186B2 (en) * | 2006-01-18 | 2009-02-10 | International Rectifier Corporation | Current sense amplifier for voltage converter |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110176694A1 (en) * | 2010-01-13 | 2011-07-21 | Schurr Thomas H | Multi-port combiner for an audio amplifier |
US8717070B1 (en) | 2013-03-12 | 2014-05-06 | Cypress Semiconductor Corporation | Multifunctional configurable analog circuit block, methods, and integrated circuit devices having the same |
WO2024084911A1 (en) * | 2022-10-17 | 2024-04-25 | ローム株式会社 | Voltage monitoring circuit, semiconductor integrated circuit device, vehicle, control device, switching regulator, and power supply device |
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US20090058380A1 (en) | 2009-03-05 |
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